Crotalus is a genus of venomouspit vipers found only in the Americas from southern Canada to northern Argentina. The name comes from the Greek word krotalon, which means "rattle", referring to the rattle on the end of the tail. There are currently 29 species recognized.
↑McDiarmid RW, Campbell JA, Touré T (1999). Snake Species of the World: A Taxonomic and Geographic Reference, Volume 1. Washington, District of Columbia: Herpetologists' League. 511 pp. ISBN1-893777-00-6 (series). ISBN1-893777-01-4 (volume).